Screw-propeller.



No. 653,979. Patented July 17, I900- J. B. ALTMAN.

SCREW PROPELLEB.

(Application filed Mar. 10, 1900.}-

(No Model.)

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JOHN B. ALTMAN, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-HALF TO CHARLESW. TREFNY, OF SAME PLACE.

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 653,979, dated July17', 1900.

Application filed March 10, 1900. Serial No. a 8 (No model-1 To all whomit may concern.-

Be it known that I, JOHN B. ALTMAN, a citizen of the United States,residing at St. Louis, State of Missouri, have invented certain new anduseful Improvements in Screw-Propellers, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, forming a part hereof.

My invention has relation to improvements in screw-propellers; and itconsists in the novel arrangement and combination of parts more fullyset forth in the specification and pointed out in the claims.

In the drawings, Figure l is a side elevation of a ship, showing myinvention applied thereto. Fig. 2 is a side elevation of the propeller.Fig. 3 is a similar view, with a portion of the blades and theelliptical shell broken away, and Fig. 4. is a section on line 4 4 ofFig.

The object of my invention is to construct a screw-propeller which willdevelop a maximum amount of efficiency and at the same time permit thefree passage of the water over the edges of the blades thereof, therebypreventing eddying of the water, but insuring a maximum contact betweenthe water and the outer surface of the blades.

In detail the invention may be described as follows:

Referring to the drawings, 1 represents a section of a ship, 2 the shaftthereof, and 2 the terminal semi -elliptical head thereof. Adapted to bepassed over said head is a hollow shell 3, secured to the head 2 byrivets 4. The shell 3 (as well as the head 2) is substantially of theform of the half of a prolate ellipsoid, the periphery of the shellbeing provided with spiral blades 5 5' of uniform width, whereby theouter edges thereof follow the contour of the ellipse, being providedwith forwardly-deflected flanges 6 6, respectively, whereby during therotation of the propeller the water slips or flows over said flangeswithout eddying, and hence insuring close contact between the water andthe blades at all times.

By making the longitudinal section of the propeller-body elliptical thelatter penetrates the water in direct proportion to the resistanceoffered to its rotation, the area of the the peculiar disposition of theblades about the shell, it being observed that the outer cutting edgesof the blades are disposed diametrically opposite to one another at theapex of the ellipse, the respective blades thence embracing the shell insuch manner that the wraps of one blade on one side of the shell intersect the corresponding wraps of the other blade on the opposite sideof the shell, the ends of the blades terminating at the base of theshell, also at the points diametrically opposite to one another.

Having described my invention, what I claim is 1. A screw-propellercomprising a body portion substantially of the form of half a prolateellipsoid, and blades of substantially-uniform width disposed about saidbody portion,

and having their outer edges following the contour of the surface of thebody portion, the said outer edges being provided withforwardly-deflected flanges, substantially as set forth.

2. A screw-propeller comprising a shaft, a terminal head for said shaft,a shell passed over said head, and being substantially of the form of asection of a prolate ellipsoid, and blades disposed about said shell andhaving their outer edges following the contour of said shell,substantially as set forth.

3. A screw-propeller comprising a body portion of the form of a sectionof a prolate ellipsoid, two sets of blades of substantially-uniformwidth disposed about the periphery of the body portion, the frontcutting edges of the blades being disposed in diametricallyoppositedirections, and the blades thence en circling the body portion in suchmanner that the wrap of one blade on one side ofthe body portionintersects the direction in which the corresponding wrap of the otherblade is disposed on the opposite side of the body portion, the rearends of the Wraps terminating at the base of the body portion at pointsdiametrically opposite one another, and forwardly-deflected flangesformed along the outer edges of the blades, substantially as set forth.

4:. Ascrew-propellercomprisinga body portion of the form of a section,of a prolate ellip-' soid, two sets of blades disposed about theperiphery thereof, the front cutting edges of the blades being disposedin diametricallyopposite directions at the apex of the ellipsoid, theblades thence encircling the body portion in such manner that the wrapof one blade on one side of the body portion intersects the direction inwhich the corresponding wrap of the other blade is disposed on theopposite side of said body portion, the rear ends of the bladesterminating at the base of

